Bench type seats have been a popular feature in automobiles for many years. A typical bench seat includes a seat cushion and a backrest cushion supported on a unitary seat frame. The seat frame is supported above the vehicular underbody upon two spaced adjustment tracks, one adjustment track adjacent the driver side door and the other adjustment track adjacent the occupant side door. The adjustment tracks are each fixedly anchored to the #2 and #3 reinforcement bars extending transversely across the underbody. An occupant restraint system is usually associated with the seat for restraining an occupant in the seat in an emergency situation.
Generally an occupant restraint system includes a seat belt harness comprised of a lap belt and a shoulder belt which merge at a clasp structured to releasibly engage a manual buckle mechanism. The buckle is typically attached by a flexible strap directly to the underbody and thus functions as an anchor when the occupant restraint system is placed under load. A dedicated reinforcement point for the buckle attachment is provided on the underbody rearwardly of the #3 reinforcement bar in areas flanking the tunnel portions of the underbody to adequately resist anticipated loads and limit the well-known phenomenon of excursion caused chiefly by underbody flexure.
One such buckle is provided for the each driver side and passenger side occupants of a bench seat. The buckles normally extend between the seat cushion and the backrest cushion on the inboard side of each of the driver side and the passenger side of the bench seat for easy accessibility when joining or disjoining the seat belt harness and buckle assembly. Because the prior art buckles are anchored to the underbody, comfort and use difficulty may be encountered when the seat is adjusted between forward and rearward positions to comfortably orient the driver.
If the driver is particularly small in stature, the seat will be adjusted forwardly to the maximum extent of the seat adjustment mechanism. This relative movement of the seat causes the underbody-anchored buckle of the occupant restraint system to become positioned below and behind the seat cushion. Thus, a small statured occupant must often search and grope for the buckle when joining and disjoining the seat belt harness. Searching for the buckle behind or below the seat cushion is particularly aggravated when in an unfamiliar vehicle, when low lighting conditions or disagreeable weather conditions exist. Also, with the buckle positioned below and behind the cushion of a forwardly adjusted seat, the lap and/or shoulder belts may wrap around the seat cushion in such a manner causing an uncomfortable condition.
Alternatively, if the driver is large in stature, the bench seat assembly will be adjusted fully rearwardly such that the buckle anchored to the underbody will be positioned significantly above and forwardly of the seat cushion. Thus, when the buckle is connected to the seat belt harness, the buckle may lay uncomfortably across the large driver's leg or in some other way cause discomfort due to its position above the seat cushion. Also, the upwardly projecting buckle may interfere with occupant and/or cargo sliding movement laterally across the bench seat.
The prior art has sought to overcome these difficulties problem by providing a mechanism to move the buckle in unison with the seat during fore and aft adjustment. In this manner, the buckle is always presented in the same position relative to the seat cushion regardless of the fore and aft adjustment position. According to this technology, the buckle is attached to a sliding carriage below the bench seat. The carriage is operatively carried on a tooth bar mechanism. The tooth bar is pivotally connected to the dedicated rear tunnel reinforcement point behind the #3 reinforcement bar mentioned above. By anchoring the tooth bar rearwardly of the #3 reinforcement bar, the force vector created along the buckle when the occupant restraint system is placed under load is substantially in line with the point of attachment of the tooth bar. In other words, the prior art solution to moving the buckle in unison with the seat during fore and aft adjustment requires ultimate anchoring of the buckle to an underbody reinforcement point provided at or near the tunnel and the #3 reinforcement bar, which in actuality has no usefulness other than to anchor the buckle to the underbody.
Many automobiles manufactured today are designed so that the consumer may choose whether a bench seat or split seats are to be installed. The underbodies of such are exactly the same for economic reasons, regardless of whether a bench seat or split seats are to be installed. The primary draw back of the prior art becomes evident when it is understood that a split seat does not require the special underbody reinforcement point behind the #3 reinforcement bar because the buckle can be anchored directly to the seat track adjustment mechanism. Therefore, because the automobile manufacturer will only make one underbody style and the bench seat underbody requires the special underbody reinforcement area for the buckles, it logically follows that all underbodies must include the dedicated underbody reinforcement point behind the #3 reinforcement bar regardless of whether a bench or a split seat is to be installed.
Because of their popularity, more split seats are installed in automobiles than bench seats. In the minority of prior art underbodies to receive bench seats, the dedicated underbody reinforcement is necessary. However, the underbody reinforcement area provided behind the #3 reinforcement bar in the majority of vehicle underbodies having installed split seats is redundant and hence wasteful. It will be readily appreciated that significant cost and weight savings can be realized by eliminating the dedicated underbody reinforcement point altogether, yet the prior art has no known structure for properly anchoring the seat belt buckles of a bench seat to the underbody except by the reinforcement structure behind the #3 reinforcement bar. Therefore, according to prior art technology, all vehicle underbodies are manufactured in conformity having a dedicated underbody reinforcement point behind the #3 reinforcement bar, which is completely redundant and wasteful in split seat applications.